The invention relates to a valve assembly with a leak-free seal, including in a duplex fluid filter assembly.
The invention arose during development efforts relating to a duplex fluid filter assembly. A duplex filter head has first and second filters attached thereto for alternate duty. The duplex head provides a first flow passage through the first filter, and a second flow passage through the second filter. The duplex head has an inlet and an outlet, and a valve having a first position connecting the inlet to the entrance of the first flow passage, and connecting the outlet to the exit from the first flow passage, and having a second position connecting the inlet to the entrance to the second flow passage and connecting the outlet to the exit from the second flow passage. In the first position of the valve, the first filter is on-line and on-duty, while the second filter is off-line and off-duty, and vice-versa for the second position of the valve. This enables the user to remove a dirty filter and replace it with a clean filter without interrupting operation of the engine or machine. For example, to change the first filter, the valve is moved to the noted second position placing the second filter on-line, and the first filter off-line. Fluid for the engine or machine, such as lubricating oil or fuel, is filtered by the second filter while the first filter is being replaced.
The present invention provides a leak-free seal for the above noted duplex fluid filter assembly. The invention is not limited thereto, and may be used in other valve assemblies.